A one-step sandwich enzyme immunoassay for human matrix metalloproteinase 7 (matrilysin) using monoclonal antibodies

A one-step sandwich enzyme immunoassay (EIA) system for human matrix metalloproteinase 7 (MMP-7, matrilysin, EC 3.4.24.23) was established with a pair of monoclonal antibodies prepared against the zymogen of MMP-7 (proMMP-7) purified from CaR-1 human rectal carcinoma cells and against an oligopeptide corresponding to the C-terminal domain of human proMMP-7. ProMMP-7 in samples was allowed to simultaneously react with both solid-phase and peroxidase-labeled antibodies. Sensitivity of the EIA system in the presence of EDTA was 0.05 microgram/l (1.5 pg/assay) and linearity was obtained between 0.156-10 micrograms/l (4.68-300 pg/assay). ProMMP-7 levels in human sera from healthy subjects were shown to be in the range of 10.7 +/- 18.8 micrograms/l. Gel filtration analyses indicated that proMMP-7 makes polymers after treatment with EDTA and suggested that proMMP-7 exists as polymers in normal human sera.